The emergency alert system is a national warning system that requires broadcasters, cable television systems, and radio and satellite service providers to allow the President of the United States and other authorized officials to transmit an emergency message to the public during disasters or crises. State and local authorities may also use the system to deliver emergency information, such as AMBER Alerts and severe weather information, generally targeted to a specific area.
The Federal Communications Commission (FCC), the National Weather Service, and local authorities send emergency alert system messages to broadcast service providers who, in turn, broadcast these messages to the public, for example, to television subscribers. The emergency alert system messages also include regular tests of the emergency alert system, as well as messages that warn of dangerous conditions such as thunderstorms, floods, tornadoes, hurricanes, and earthquakes, or urgent bulletins.
Because many multimedia delivery systems are very large, emergency alert system messages could be disruptive to communities that are not affected by a particular alert. For example, a National Weather Service message directed to coastal regions would be unnecessary for inland regions. A technique referred to as Federal Information Processing Standards (FIPS) filtering, allows a digital network control system to filter and send emergency alert system messages to only targeted states, counties, or subdivisions, as might be identified from a FIPS code provided within each message.